Three years ago, officials in Woodbury and Cottage Grove began looking at a fundamental but vital question: Will there be enough safe drinking water for our growing communities in the future?

Informal meetings became a task force that would include representatives from four state agencies, Washington County and several other cities. And now, work started by that panel has become enmeshed in a mountain of evidence in the state's lawsuit over water contamination in the county against 3M Co. The trial in that suit is expected to begin this year.

Even with the recent stirring of new housing developments in southern Woodbury and northern Cottage Grove, water issues are not a short-term concern, city officials said.

"It's not an issue in 2013, it's not even going to be an issue in 2020," said David Jessup, Woodbury's engineering and public works director.

Rather, the panel that became the South Washington Water Supply Work Group was looking much further into the future -- 30, 40, even 50 years from now. And the scope and complexity of those questions are why it would encompass other communities and agencies.

As much as cities like Cottage Grove and Woodbury have changed in the past several decades, they will look even more different as the population keeps growing and new business and industry arrives. "All of these things are going to require more water," Jessup said.

In November 2010 -- a month before the state filed its suit against 3M -- the two cities asked for help from the Metropolitan Council in its water supply study, said Bonnie Kollodge, spokeswoman for the regional planning agency.

According to agency documents, Woodbury and Cottage Grove face two key challenges in that long-term water supply planning.

First, population growth by the year 2050 will put more pressure on the Prairie du Chien/Jordan aquifer. The aquifer (the same one feeding shrinking White Bear Lake) is a vast underground store of water sandwiched among rock and sand which is drawn to serve the two cities and many other communities as well. The timeframe is uncertain, one model has found, but more than half the available water in the aquifer could one day be drawn down in the area.

Secondly, that groundwater has been contaminated by chemical compounds called perfluorocarbons, or PFCs, which were legally dumped over decades by 3M at four sites in Washington County: its plant in Cottage Grove and sites straddling the boundary of Woodbury and Cottage Grove, in Oakdale and Lake Elmo. They were also dumped into the Mississippi River. Those PFCs, which linger in the environment for years, are the source of the state's lawsuit.

While PFC levels have been below what is deemed a risk to people by the Minnesota Department of Health, those standards "could change in the future as research continues into the effects of these chemicals on human health," according to Metropolitan Council documents.

Once the scope of the water supply study was outlined by the Metropolitan Council, Kollodge said, engineering consultants were hired to begin the work. However, they were the same consultants the state had hired in its efforts to prepare its case against 3M.

"The consultants from the state used our group as a sounding board," Jessup said.

Since the consultants were retained by the state's attorney and are looking at the same issues, it was decided that the study as it pertains to the two cities would be put on hold, though discussion of water supply issues is ongoing, Kollodge said.

That information will answer a key question in the lawsuit: Is 3M liable for PFC damages, including the potential cost of supplying water to cities like Woodbury and Cottage Grove?

In 2007, the Minnesota Pollution Control Agency and 3M reached an agreement requiring the company to clean up PFCs, and those efforts are ongoing. However, that agreement did not address 3M's liability for injuries to the state's natural resources, said Ben Wogsland, spokesman for the state attorney general's office. According to the suit, that could include "substantial costs to provide alternative sources of groundwater for domestic and other uses."

Neither Woodbury nor Cottage Grove is a party in the state's lawsuit against 3M, though Lake Elmo and the Metropolitan Council have joined as intervenors.

But if 3M ultimately is found liable for the damages, other communities would still collect damages, Jessup said. But the state has to prove 3M caused the damage, and then the cost implications would have to be determined.

So far in the case, more 6 million documents have been filed, and depositions taken from more than 50 expert witnesses.